1. Field of the Invention
The present invention relates to an image forming apparatus provided with an auxiliary power source device for storing electric power of a commercial power source and supplying the stored electric power and a fixing device having a heat generator for generating heat with electric power supplied by the commercial power source and a second heat generator for generating heat with electric power supplied by the auxiliary power source device.
2. Description of the Related Art
Conventionally, there have been used image forming apparatuses such as a copying machine, a printer, a facsimile machine, a scanner, and a so-called complex machine. In such image forming apparatuses, there is provided an auxiliary power source device for storing electric power of a commercial power source and supplying the stored electric power. Further, other than a first heat generator for generating heat for a fixing processing by using electric power supplied by the commercial power source, a fixing device is provided with a second heat generator for generating heat for the fixing processing by using electric power supplied by the auxiliary power source device. When the fixing device is started up, fixing rollers and the like can be heated quickly with use of the first and second heat generators.
Here, there is a case where a capacity of electric power of the auxiliary power source device runs short when it is required to start up the fixing device. Therefore, there has been a proposed manner of starting up a fixing device by using only electric power supplied by a commercial source at the time when the capacity of the auxiliary power source device runs short (refer to Japanese Patent Unexamined Publication Nos. 2003-257590, 2004-200149, and 2006-058731). On the other hand, there is a case where a jam (sheet jam) occurs in an image forming apparatus during an image forming operation is performed. When a sheet jam occurs, the image forming operation is stopped, and the occurrence of the sheet jam is displayed on an operation panel to allow a user to open an apparatus cover and treat the sheet jam. Then, the image forming operation is restarted after when the user treats the sheet jam and close the apparatus cover.
When such sheet jam occurs, all operation of the apparatus is stopped, and generation of heat by the two heat generators is stopped since a user might open the apparatus cover and touches inner parts of the apparatus. Consequently, the temperature of fixing rollers and the like of the fixing device lowers. After the sheet jam is treated, it is necessary to start up the fixing device. However, when no electric power is left in the auxiliary power source device, the second heat generator cannot generate heat. Therefore, the fixing device cannot be started up quickly. Further, if the auxiliary power source device is charged again when the image forming is performed after the treatment of the sheet jam, the second heat generator can be used only after the charging is completed. However, the processing delays because of the time necessary for the charging.